Dear Arpit,

In order to be eligible for NDA your minimum age should be 16.5 years and maximum age should be 19.5 years.

You can check the educational qualification below

Army Wing: Candidates applying for Indian Army must have passed class 12/HSC in 10+2 pattern of School Education or equivalent examination conducted by a State Education Board or a University

Air Force, Navy and Naval Academy of National Defence Academy : Candidates applying for Air Force, Navy and Naval Academy must have passed class 12/HSC in 10+2 pattern of School Education with Physics and Mathematics conducted by a State Education Board or a University

Good luck!!